The nuclear crisis at Fukushima Daiichi has, alas, now evolved into more of a saga. The last seven days of events has been acted out in slow motion compared to the first dramatic week (dating back to almost a month ago), but there continues to be plenty of headaches for TEPCO — and no clear sign of things being locked down any time soon. The economic cost of the earthquake and tsunami has now been put at ~$300 billion, and will probably rise further in the coming months.

I last wrote an update post a week ago (although I’ve also been providing daily updates in the comments section), so it’s best to start this one by looking at what’s happened, day by day, since then. Here is my somewhat potted update summary, with just the main points highlighted.

It was 2nd of April (Saturday) that it was first reported that a stream of contaminated water was flowing into the ocean, leading to extremely high radiation levels immediately offshore of the plant. The water appeared to be coming from the vicinity of Unit 2, and after some diagnostics, including the use of a coloured tracer (dye), the source was identified as a 20 cm crack in a maintenance pit which lies between Unit 2 and the sea. The pit is used to hold cables to power the seawater pumps. Its radiation was measured as ~1 Sv/hr.

In the evening of 2 April, concrete injection was trialled as a means to seal the crack, but this failed. Throughout 3 April, a second attempt was made, this time via injection of a water-absorbing polymer, mixed with sawdust and shredded paper (to aid in the swelling process). This also did not set. To mitigate the leaks to the ocean, plans were then made to try and pump a large amount of the contaminated water out of the pit and into storage, including some barges that had been anchored offshore.

It was also announced by TEPCO that the bodies of the two workers who had been missing in the turbine building of Unit 2 since the tsunami struck had been recovered on March 30. They’d apparently been drowned when the site had been innundated. The image above illustrates just how devastated the landscape around the plant is after the monster wave (14 m in this area of the coastline) wreaked its havoc.

… these three are the only deaths at nuclear power plants from the earthquake, tsunami and subsequent nuclear emergency. No effects on health or significant contamination cases have been identified among the general public evacuated from the area. The tsunami travelled up to five kilometres inland in Fukushima prefecture, causing a 1113 deaths with 4626 more people still missing. The totals for Japan as a whole are 12,087 dead and 15,552 missing as of today.

Among the 370 workers working to bring stability to the damaged reactor units of the Daiichi plant, 21 have so far experienced radiation doses of over 100 millisieverts.

By Monday, there was mounting concern about the possible build up of hydrogen within the containment buildings of Units 1-3 — and some risk of a repeat of the earlier chemical explosions, perhaps this time within the drywell, which would, in turn, risk damaging the reactor pressure vessel (RPV). To counter this, plans were made to inject inert nitrogen gas (which makes up 78% of our atmosphere), to dilute the hydrogen and expel oxygen. (This had commenced this operation in Unit 1 by Thursday 7 April.)

On 5 April, the flow from the cable storage pit had been linked to a faulty duct joint. On Wednesday 6 April, a large volume of polymer coagulant was forced into the pit and adjacent gravel, and this was reported as being successful in hardening and sealing the leak. However, water had continued to accumulate and so 11,500 tonnes of mildly contaminated water was released into the ocean to allow for storage of the highly radioactive water. This is what apparently led to the high levels of iodine-131 detected soon after in the sea water in the immediate vicinity of the plant.

The main development in the last day has been preparation of a huge floating platform (136 x 40 m) next to the site, in order to store contaminated water. It is expected to arrive on site in less than two weeks.

In Unit 1 fresh water has been continuously injected into the reactor pressure vessel through feed-water line at an indicated flow rate of 6 m3/h using a temporary electric pump with off-site power. In Units 2 and 3 fresh water is being injected into the reactor pressure vessels continuously through the fire extinguisher lines at indicated rates of 8 m3/h and 7 m3/h using temporary electric pumps with off-site power.

The reactor pressure vessels’ temperatures remain above cold shutdown conditions (normally less than 95 °C). In Unit 1 indicated temperature at the feed water nozzle of the RPV is 224 °C and at the bottom of RPV is 117 °C. The pressure in the RPV is increasing as indicated on both channels of instrumentation. NISA has indicated that some instruments in the reactor vessel may not be working properly. Drywell pressure is increasing slightly due to the addition of nitrogen. In Unit 2 the indicated temperature at the feed water nozzle of the RPV is 144 °C. The temperature at the bottom of RPV was not reported. Indicated Drywell pressure remains at atmospheric pressure. In Unit 3 the indicated temperature at the feed water nozzle of the RPV is 88 °C and at the bottom of RPV is 112 °C. Fresh water was sprayed onto the spent fuel pool by concrete pump vehicle (50t/h) from 21:53 UTC, 6 April.

In the news this week, there were all sorts of ongoing speculation, most of it unfounded or at least lacking any concrete evidence. Probably the strangest was the declaration by US Rep Markey that he’d been informed by the NRC that Unit 2 had undergone a complete meltdown — a claim that was later quashed by an NRC official, who said that they’d supplied no such information. Go figure.

A few other things:

(i) This is an interesting blow-by-blow summary of the Fukushima Daiichi events, with lots of interesting pictures, produced by someone at AREVA. However, it may (?) have since been yanked by AREVA, and I can’t vouch for the accuracy of all the data — or speculation. Still it’s an interesting overview.

(iii) There is an upcoming debate for those in the UK, on the contention: “Nuclear power is still worth it“, to be held on Thursday 14 April 2011 at the Royal Geographical Society (RGS), London. Here is an example of an earlier event:

They’ll be streaming the new event free and live from their site, and one of the organisers, Kit Cockburn, tells me that they’d also be happy to give a 50% discount on tickets to BNC readers, should they want to watch the debate in the venue itself (the discount code is ‘NUCLEAR’).

The concentration of radioactive nuclides from the seawater sampled at the screen device (installed to remove waste before the intake of seawater) of Unit 2 and sampled near the seawater discharge point (south side) of Fukushima Daiichi Nuclear Station were as follows:

temperature directly above the second containment building by thermography measurement (degrees Fahrenheit)

–

86

–

–

–

–

–

4/8

7:30AM

–

–

–

–

Amount of water in total shot/injected to the spent fuel storage pool (tons)

90

299 – 314

5,048

1,531

–

–

as of 4/8

7:00PM

as of 4/8

7:00PM

as of 4/8

7:00PM

as of 4/8

7:00PM

–

–

*1: Minus figure means that water level is below the top of the fuel rods.

*2: This figure is under investigation.

Fukushima Daiichi Unit 1 reactor

As of 6:00PM on April 8, injection of nitrogen gas into the primary containment vessel to prevent an explosion by accumulated hydrogen gas continues.

As of 6:00PM on April 8, the injection of freshwater into the reactor core continues.

Fukushima Daiichi Unit 2 reactor

As of 6:00PM on April 8, the injection of freshwater into the reactor core continues.

Fukushima Daiichi Unit 3 reactor

At 5:08PM on April 8, TEPCO began to shoot water aimed at the spent fuel pool, with a specialized vehicle normally used for pumping concrete.

As of 6:00PM on April 8, the injection of freshwater into the reactor core continues.

Fukushima Daiichi Common Spent Fuel Pool

At 7:20AM on April 8, the temperature of the spent fuel pool: 82.4 degrees Fahrenheit.

Others <Influences of the aftershock occurred at 11:32PM on April 7>

Fukushima Daiichi Nuclear Power Station

As of 4:00PM on April 8, no significant changes have been detected at monitoring posts at the site.

Fukushima Daini Nuclear Power Station (Unit 1, 2, 3 & 4)

Plant operation was suspended at all units when the aftershock occurred.

As of 4:00PM on April 8, no significant changes have been detected at monitoring posts at the site.

Onagawa Nuclear Power Station (Unit 1,2 & 3)

Plant operation was suspended at all units when the aftershock occurred.

The spent fuel pool cooling system was suspended automatically but has been recovered immediately.

As of 4:00PM on April 8, no significant changes have been detected at monitoring posts at the site.

Higashidori Nuclear Power Station

Plant was under periodical maintenance when the aftershock occurred.

Immediately after the external power was lost, backup diesel generators turned on to supply electricity to maintain the cooling system of the spent fuel storage pool.

As of 4:00PM on April 8, no significant changes have been detected at monitoring posts at the site.

Tokai Daini Nuclear Power Station

Plant operation was suspended when the aftershock occurred.

As of 4:00PM on April 8, no abnormality has been reported.

Tomari Nuclear Power Station (Unit 1, 2 & 3)

All units were under normal operation when the aftershock occurred.

As of 4:00PM on April 8, all units are under normal operation.

Rokkasho Reprocessing Plant and Accompanying Facilities

Immediately after the external power was lost, backup diesel generators turned on to supply electricity..

As of 5:00PM on April 8, power supply has been switched from backup power generation systems to the external power. It was confirmed that no fire, damage to equipment, injuries to personnel occurred. Radiation levels were measured at a normal level of safety.

Back when the Chernobyl incident was happening I recall the media was worried about a meltdown. Back then, my understanding was that a meld down was when the whole reactor got so hot that it melted its way into the earth in a way that could never be controlled. Now a melt down only seems to be some melting of fuel rods. Has the term meltdown become meaningless? In one case it is to be feared and in the other it hardly seems to matter.

Robert, you’re right… it’s basically just a buzzword without a good scientific definition.

If “meltdown” means that it melts through to China or something (the “China Syndrome”), then of course it’s meaningless because it’s utterly impossible nonsense.

But if “meltdown” means fuel melting to some partial extent inside the reactor pressure vessel inside the containment, like at TMI and possibly at Fukushima too… well, “meltdown” isn’t that scary, because it’s not actually likely to hurt anyone at all.

More recent reactor designs such as the EPR are designed to catch and cool a full core meltdown – and you wouldn’t even notice it when standing next to the reactor building!

The media like to portray meltdowns as apocalyptic events that will kill thousands if not millions, but what actually makes nuclear accidents dangerous is high dose from a large release of radionuclides. If your design takes into account full meltdown retention and cooling then meltdowns indeed become unimportant for public health. In stead containment failure combined with meltdown becomes dominant. Better make your containment aircraft crash, earthquake and tsunami proof.

Reprocessing plants release large amounts of radionuclides all the time, but the dose is tiny because the release is almost exclusively noble gasses that just float away in the higher atmosphere (unless the plants are poorly managed like Hanford). The Pacific ocean is decaying at a rate of 8000 EBq. Which is 8,000,000,000,000,000,000 radioactive decays per second. This does not mean the Pacific is dangerously radioactive because of its huge bulk making dose very tiny even if you swim in there all the time.

What would be your statement on the AREVA report about the spend fuel pool of Reactor 4 – there the following possible consequences are listed: “Core Melt on Fresh Air, nearly no retention, large release. (maybe it’s already discussed, if possible could you point me to the discussion?)

(1) citation needed
(2) stuff like this won’t reassure people who want to know such problems _get_ noticed.

You’re trying to defend the industry, but this kind of defense makes new readers wonder why it’s needed.

It’s not needed. You can cite good sources and you can give information that’s evenhanded and acknowledges the range of possibilities, not take only one side and post only info favoring one side.

Please try.MODERATOR
Hank- would you please state the name and time of the comment you mention.
I am just looking back at the overnight posts and can’t see this particular comment so I can’t edit and ask for refs.

[Comment deleted. Violation of the citation rule]
b.MODERATOR
To everyone -a reminder of the rule.

BARRY BROOK The commenting rules are not meant to be confusing, they’re meant to be logical. This is not a forum for cut-and-pasting slabs of text, with no other comment other than a link. Tell people why you think they should be interesting in reading this, and what it means for this discussion. Otherwise, you’re not thinking and not contributing. Simple as that.
I’ll add a new clause to the commenting rules:
Citing literature and other sources: appropriate and interesting citations and links within comments are welcomed, but please DO NOT cite material that you have not yourself read, digested and understood. As a general rule, please introduce any and every link or reference with a short description of the material, your judgement on its quality, and the specific reason you are including it (i.e. how it is relevant to the discussion).

Hank Roberts, this is meant to be explanatory to the issue of core melt versus large radionuclide release. Adding a core catcher is adding a layer of defense in depth that cannot fail. It is unique in industrial safety to have both PRA and effect based mitigation. There is much work done on core catchers, here is an example:

If you google core catcher you can find a lot of good stuff beyond that.

I am not defending the industry. As a matter of fact, most of my pay is from design and controls of oil infrastructure including oil terminals. Having seen first hand what damage fossil fuels do, all the time, not just what they can do in an accident, just regular damage, I’ve come to the point of willing to look for another job and prefer for reason and rational choice to be victorious over personal interests.

Thanks Cyril, I agree — just trying to say, as I say to myself every time I post — step back, imagine someone coming along reading this stuff later on or dropping into one posting via a Google search, and try to always give cites and enough information that the reader gets helped to make sense of this.

While it’s easy to fall into treating this like conversation with people who remember what was said yesterday — it’s actually writing that persists, and gets read later out of order by people searching.

Tiresome, I am, I know (wry grin). I applaud your posting more context, it helps a lot. Barry ought to give you a topic to go into this stuff.

Was the length of time required for the TMI cleanup due to purely technical reasons? From one account of what happened at TMI: “Anti-nuclear groups across the country filed numerous lawsuits effectively delaying anyone actually opening the reactor to see what happened to the fuel.” Three Mile Island and the China Syndrome

The same groups often point to the high costs and plant construction delays of the nuclear industry as a reason why nuclear energy shouldn’t be pursued– but to what extent are the cost increases and delays exacerbated by the attacks from these same groups?

Wow, the claims of the anti in the intelligence squared debate were shocking. He starts off by saying that if external power was lost AND back up power, then the cooling water would boil off within a few hours. A few hours? Even if that were the case I’m pretty sure it would be ample time to get some extra back up diesels in. Then he goes on to say that we are only a few hours away from a nuclear explosion – now that’s very disingenuous and and appeal to emotion .MODERATOR
Video of the debate is embedded in the article.

2 out of three diesel generators not working? this simply should NEVER happen.

——————–

i am also surprised by the slowness of response in other countries. it is pretty obvious that measures must be taken immediately at plants that are threatened by quakes, tsunamis or both. even just temporary emergency measures, like sandbags or movable floodwalls should be moved into position.

it is also clear that the problem was loss of emergency electricity. moving in additional diesel generators, fuel and adding a couple of connections doesn t cost anything and should be done now.

the situation at Fukushima also demonstrated that there is a problem with spent fuel pools at the top level of reactor buildings. old fuel should also be moved out of those buildings in reactors all over the world immediately.

[Deleted speculative scientific comment unsupported by refs/links.]MODERATOR
If you want to raise these personal ideas/speculations, the correct forum is the Fukushima Open Thread where BNC rules are more relaxed. Please re-submit on that thread.We do not have the facility to transfer comments to the correct thread.

There are a few scary terms – meltdown, nuclear explosion – that are getting applied to less and less truly scary situations. The cachet, so as to speak, of the original word has been appropriated to situations which do not intrinsically warrant it. There are other examples throughout the language; it is not unique to the nuclear industry.

“Nuclear explosion” is a pretty egregious example. It is a well-defined term that simply does not apply to anything that happens at a nuclear power plant. I wouldn’t advise anyone to expect mere accuracy to stop the misusage of a term that is expedient for the speaker, however. But it can be defeated – if the discussion and emphasis on explosions in general will not distract too much.

Discussion of meltdown requires a little more flexibility. If it is being used (as often) to mean something that is automatically disastrous on a wide scale, then it more-or-less must also be talking about corium reaching groundwater (which is what I would take to be the “china syndrome”, rather than something which continues into the ground). Despite the massive quantities of corium produced in Chernobyl, and conditions that prevented anyone taking concerted action, this did not happen there, and as such can be comprehensively dismissed. Lesser “meltdowns” should be acknowledged as having far less effect, mostly confined to the plant itself. A useful guide here is that the other three reactors at Chernobyl were operated post-disaster.

There’s some tsunami photos from the other plant (Daini) — note the scale of things, e.g. the seawall in the background. If I understand correctly, the elevation of the road is about 12 meters above sea level:

Wow, I just watched that Royal Geographical Society debate clip and I hope the nukies got to reply to the ridiculous charge that “we are never more than a few hours away from a NUCLEAR EXPLOSION!” Where do they dig up these people!?

The likelyhood of any more air release of radionuclides has become pretty remote. Why does not the Japanese government collapse the evacuation zone a bunch and let people who still have homes return to them? Looks to me at this point that they are just inflicting hardship for no good reason.

Moderator, I believe EN is referring to the intelligence squared debate clip embedded in the article above.

EN – I was shocked by the video too. See my comment on the YouTube video. Please add your own 2 cents too.MODERATOR
Ooops! Thank you Huw. There was so much to catch up on overnight that I haven’t yet watched that video myself!

appears to indicate dose readings in the drywell (D/W) and suppression chamber (S/C) which is the torus structure. The torus contains water with scrubbed fission products in it so we’d expect the high but declining Sievert readings there (fission products decay). Readings in the drywell would also be high, being next to the reactor vessel, though that last spike seems weird.

[Comment deleted. Wrong thread]MODERATOR
Please re-submit your comment to the Fukushima Technical Open Thread where this discussion is taking place. We do not have the facility to move comments between threads.

Your graph is of the dose rates in the air in the drywell (D/W) and suppression chamber (torus) (S/C), as measured by the Containment Atmospheric Monitoring System (CAMS). The graph you linked is not current; a later measurement (4/8 13:00) sees the D/W dose fall to 68.3 Sv/hr, and after that it goes into an error state.

(This won’t help you interpret the data, but I thought these links could be useful).

But the plant owner, the Tokyo Electric Power Company, said the gauge used to measure radiation was most likely broken.

The high radiation was measured in the drywell of Reactor No. 1, directly below the reactor pressure vessel and part of the primary containment that is a crucial barrier preventing the escape of radioactive materials. The drywell reading raised the worrisome possibility that highly radioactive water had escaped, and perhaps even material from the nuclear core, although this was far less likely.

…And on Saturday, Eliot Brenner, a spokesman for the [NRC], agreed with the power company’s assessment that the high reading in the No. 1 reactor was most likely in error because there had not been a sharp increase in pressure or temperature in the drywell.

dear Moderator, the statement “a glass can not contain more water than it can hold” does NOT require a citation.

the same is true for a reactor.MODERATOR
Your statement was not “a glass can not contain more water than it can hold” i.e. that the reactor was overflowing. But that you “thought/guessed” it was leaking. Why did you think so and where are your sources.

“Tokyo (CNN) — Japan may set standards for long-term radiation exposure that would effectively extend the evacuation zone around the damaged Fukushima Daiichi nuclear power plant, a top government official said Thursday, as a strong new aftershock rattled the area

Government readings show that people beyond the current restricted zone may be exposed to dangerous long-term doses of radiation even though the readings fall below levels that now require an evacuation, Chief Cabinet Secretary Yukio Edano said.

“It is the time for the government to consider setting another category for accumulated exposure,” Edano, the government’s point man on the crisis, told reporters Thursday evening….”MODERATOR
You were safe from the brush-cutter overnight – the moderator was asleep :-)

TEPCO is now posting graphs as well as text charts, this is helpful. This is from their press release page, described as “﻿﻿Fukushima Daiichi: the result of the dust nuclide analysis” (showing both “volatile” and “particle”)
(whatever that means, I haven’t found it explained)

PS — I think it’s more likely that’s a “2.200” in the radiation reading; there’s a little blurry pixel there; the’ve used a font for their PDFs that has all the digits slightly overlapping so a decimal point gets lost in a “2” where it’s visible next to a “0”

Government readings show that people beyond the current restricted zone may be exposed to dangerous long-term doses of radiation even though the readings fall below levels that now require an evacuation

I’m puzzled their graphic shows venting from the torus being sent out through the “stack” after passing through an acronym that’s probably the standard filter system. The “stack” would be the very tall tower, but the pipes to that visible in the satellite photos appear to have been broken off by the tsunami. Does anyone know where the venting from the torus is going, on each reactor?

Harry — please be careful. You attributed words to me, from something I quoted directly from the news story cited.

This is the full paragraph:

Government readings show that people beyond the current restricted zone may be exposed to dangerous long-term doses of radiation even though the readings fall below levels that now require an evacuation, Chief Cabinet Secretary Yukio Edano said.

That’s not my opinion. It’s a quote. You posted radiation levels following that but not the time span.

Point from the story is — a small dose per hour still adds up to exceed the permitted dose, eventually, and releases are continuing. The evacuation levels were set for a one-time release, not an ongoing release.

That’s why they are restricting return to the area — cumulative dose can’t be capped until the releases are stopped and they don’t know how long the current leaks will continue.

Lots of detail and photographs there — more than I’ve seen anywhere else of the innards of the actual working reactor Unit 3, as it was taken apart and put back together to replace the core shroud not long ago (not sure exactly when)

So — Unit 4 had just recently been shut down and emptied of fuel so they could do this same replacement procedure of its core shroud.

The areas of concern are the ones in the line northwest of Daiichi, because some wind took fallout there and put it down as you can see here:

There appears to be 1-10 mrem/hour (10-100 microsievert/hour) in the fallout area. Not particularly hazardous but the government goal is to restrict total dose to under normal nuclear plant worker conditions which is 50000 microsieverts (50 millisieverts).

All the data, including JAIF radiation trends, does indicate that doses have been on constant decline for at least two weeks now. Highest cumulative dose in Hank’s NISA reference above is 6 millisievert. Perhaps there are some areas in the northwest fallout area that are higher, and they want to make sure people there aren’t getting above the 50 millisievert normal worker dose?

Cyril, from what I read the publicly stated concern is not about the worker dose limits — those are all adults, and being tracked for total exposure individually. Likely they’ll be watched for a long time as individuals.

Rather prolonging the evacuation is about limiting the longterm population dose residents would begin to accumulate starting with return to the area.

That can’t be known because it’s impossible to set a limit on it until all the sources adding new fallout are controlled. Tiny amounts, but from unknown sources, until they can get into all the reactor vessels and fuel pools and not just stabilize them but inventory them.

I’d imagine there’s also a practical concern about possessions and salvage being picked up and transported out of the area, and dust being disturbed.

Once the releases from the plant stop — when the only change in radiation level is the predictable decrease due to decay, the existing material — if undisturbed and left where it fell — will wash out with further rainfall, and move off roofs and streets into the soil and sewers and otherwise away from areas people will occupy on their return.

No wonder Toshiba thinks it can tear down the facility in such a short amount of time; having replaced the core shroud, they should have plenty of records and projections to use in the planning process.

Well, that and Toshiba would like to further expand its reputation in the nuclear energy market. It is common sense to make such a bold claim.

@Hank Roberts 4:39 Thank you very much for your posting of NISA’s April 4 summary of events at Fukushima NPS R1-6.

I am disappointed by NISA’s summary since I believe that some things (that persons following the situation closely know) are concealed or distorted.

Two things jumped out at me: 1) the PCV vents to the refueling floor are not shown. Instead PCV vents to a tall stack are shown (one thru a filter SGTS? and one thru a bursting disc), see slide 21. The PCV vents to the refueling operations floor are shown on the Areva slides and have been thought to be the source of H2 for explosions in R1 and R3 bdlgs. If the PCV vents to the tall stack were used instead of the ones to the refuel floor, then the source of the H2 bdlg explosionscould have been instead from the PCV containment cover seals leaking.

The other thing that jumped out at me was that there is no mention of the March 15 06:00 H2 explosion in R4 bdlg [due to H2 generated by radiolysis and/or zirc-steam reaction in the R4 SFP]. See NISA slide 32 for their R4 chronology.

Satellite photos clearly show that the damage to R4 bdlg happened after the R3 building explosion on Mar 14. It’s as if the R4 building explosion never happened in NISA’s account.. Slide 35 only talks about H2 explosions in terms of “possible concerns about spent fuel pool”. There is no assesment of the R1-R4 SFPs.

BTW, the R4 SFP temp is shown to be increasing from 84C on Mar 15 to 100C on Mar 24 (slide 40). The 100C reading has never been mentioned before.

Status of Fukushima Daiichi Nuclear Power Station
April 9th, 2011
The Tokyo Electric Power Company, Inc.

 Water is planned to be transported to condensers for Units 1 ~ 3, whilst for Unit 4, it is being considered.
Turbine Building basement Condenser Condensate Storage Tank (CST)
Unit 1 Waiting for water to be transported to condenser 13:55 April 3rd ~ Transportation to CST commenced. April 2nd:
Transportation to SP(*1) surge tank completed.
Unit 2 April 10th: Planned to be transported to condenser 13:10 April 9th: Transportation to CST completed. April 1st:
Transportation to SP surge tank completed.
Unit 3 Waiting for water to be transported to condenser Planning transportation to CST March 31st: Transportation to SP surge tank completed.
(*1) SP: Suppression Pool

・ 5:38 April 6th: Confirmation of stoppage of leakage from beneath the supply cable pit.
・ April 6th ~ Leakage part was further treated by rubber board and fixer. Stoppage of leakage and monitoring is continuously done.
 Other measures (April 5th)
・ For reducing ocean spillage, steel walls are being set up (April 9th ~). Silt fences are being prepared.
・ Setup of large sandbags at banks south of outlet is cancelled following bad weather.

・ April 3rd 9:52 ~ 11:15 Transportation of water from Burge 2 to Burge 1
・ April 4th 11:54 Burge 2 sailed into port after freshwater supply. On standby.

・ April 9th: Plant condition check by unmanned helicopter was cancelled due to bad weather.
・ April 9th: Spraying of inhibitor was cancelled due to bad weather.
・ Receipt of an order regarding interpretation of safety regulations on emergency generating facilities on April 9. Now Japanese utilities are required to have two emergency generating facilities operable which connect to necessary emergency alternate-current high-voltage bus line for each nuclear reactor. Please see details bellow.

=======
TEPCO received an order document, “Regarding interpretation of safety regulations on emergency generating facilities”, from Nuclear and Industrial Safety Agency (NISA), Ministry of Economy, Trade and Industry.
Based on this order, in conjunction with an order received on March 30, we will take actions immediately.

* Translation of the Order document: Regarding interpretation of safety regulations on emergency generating facilities by NISA

The Earthquake Off the Coast of Miyagi Prefecture occurred on April 7, 2011 and Higashi-dori Nuclear Power Station of Tohoku Electric Power Company lost the offsite power and emergency generating facilities started up to maintain the power source. Although the offsite power has been restored, emergency generating facilities shut down due to some troubles. Thus, it was reported as a failure to secure the restriction of operation regulated in the safety regulations.
Amongst the matters on operation of nuclear reactors facilities in the safety regulations stipulated in such as Article 16.7 of the current “Rules on the Installation and Operation of Commercial Power Reactors”(No. 77 of Ordinance of Ministry of International Trade and Industry, of Showa 53 (of 1978)), the interpretation on restriction of operation requires one emergency generating facility operable for each nuclear reactor in the condition of cold shutdown such as during regular inspections and fuel replacement (which includes the cases of storing spent fuels in spent fuel pools). However, in consideration of the accident of Fukushima Daiichi Nuclear Power Station caused by Tsunami induced by Tohoku-Chihou-Taiheiyo-oki Earthquake, 2011, it is extremely important to secure power source. Therefore, the interpretation was amended to require two emergency generating facilities operable which connect to necessary emergency alternate-current high-voltage bus line for each nuclear reactor (when power stations have more than one nuclear reactor, they can count the number of emergency generating facilities of other units which are connected to the necessary emergency alternate-current high-voltage bus line.)

As a result, it is required to immediately take actions for emergency safety measures, ordered on March 30, including securing power supply cars, fire fighting engines, fire fighting hose and others and also is required to immediately implement amendment of safety regulations of “Rules on the Installation and Operation of Commercial Power Reactors”, which fulfils the above interpretation and also is one of the safety measures for emergency, by April 28 of this year.

“Tokyo Electric Power Company has bugun using unmanned heavy equipment to remove radioactive rubble [from the area around the outside of] the Number One and Number Three reactor buildings. The debris is emitting hundreds of millisieverts of radiation per hour in some places, hindering the restoration work….

“… the most recent TEPCO hourly photo shows a barge with a crane on it (see yellow arrow I’ve added) working on the north end of the intake channel screen / wall. This equipment is probably either dredging to prepare for installation of the new contamination spread prevention screens, or else installing the screens themselves….
…
There is some data, which we’re looking at in detail, showing a spike increase in airborne contamination inside the drywells on the plants concurrent with, or shortly after, the recent ~7 scale quake off Miyagi prefecture. These readings may simply have been due to the quake shaking loose contaminated material that was already inside the drywells and which had settled .. perhaps a dry crud burst of sorts. (That’s for all you nukes out there.) We’ll keep watching these figures; they’re reported as CAMS figures on NISA / JAIF report documents… which we hasten to add are again slipping behind time-date wise. Speaking of which… NISA, we might recall, thinks that air tightness may have been lost on all three reactor pressure vessels, so that it’s also possible that the increase in CAMS readings is directly from core material. But it’s too early to tell this yet, with the sparse data we have right now.
10:01 PM Eastern Sunday 4/10 “

> veggies
Deep roots. Most coastal plants can take quite a lot of salt water (storm spray blown inland) for a brief exposure, at least from my East Coast US hurricane experience. Trees would be stripped to bare branches by a storm and leafing out in springtime green within a few days after major hurricane inundation

> movie
5 micro-sieverts/hour, for example, and their dash mounted counter alarms — can you see what the detectors are detecting? can you tell if the alarm is for airborne particles in the air inside the car, or gamma coming through the windshield?

http://geospatial.blogs.com/geospatial/2011/04/fukushima-daiichi-and-daini-casualties-among-tepco-workers-and-health-impacts-on-general-public.html
“Since the earthquake 370 workers have been working at Daiichi to stabilize the damaged reactor units. Of these 21 have experienced radiation doses of over 100 millisieverts (mSv). According to WNN nuclear workers are permitted to receive a maximum aggregate dose of 20 mSv per year. If that limit is exceeded in any year, the worker is relieved of nuclear duties for the remainder of the year. In an emergency safety regulators may raise the aggregate maximum exposure to 100 mSv. Above 100 mSv it is possible to begin to relate radiation exposure statistically to health effects, specifically cancer. March 16 Japanese authorities authorized exposures of up to 250 millisieverts because of the seriousness of the situation at Daiichi. WNN says that at this point no one has been exposed to an aggregate annual dosage of 250 mSv.”

Engineers at the damaged Fukushima Daiichi plant north of Tokyo said Sunday they were no closer to restoring the plant’s cooling system which is critical if overheated fuel rods are to be cooled and the six reactors brought under control.

Hank, I would guess they are measuring only the gamma dose rate. The total gamma exposure of their trip was probably ~40 uSv, which is about the same as an airplane flight from NY to LA according to http://xkcd.com/radiation/

[Comment deleted. Violation of the citation policy]MODERATOR
The citation policy is as follows:
Citing literature and other sources — appropriate and interesting citations and links within comments are welcomed, but please DO NOT cite material that you have not yourself read, digested and understood. As a general rule, please introduce any and every link or reference with a short description of the material, your judgement on its quality, and the specific reason you are including it (i.e. how it is relevant to the discussion).

The workers certainly seem to be greatly inhibited so as to not get their maximum doses.http://www.yomiuri.co.jp/dy/national/T110407006089.htm
Current levels at the three reactors are between 20 and 31 sieverts, down from 138-167 sieverts per hour on March 14th. “Two workers were killed in a 1999 nuclear accident in Tokaimura, Ibaraki Prefecture, after being exposed radiation levels of between six and 18 sieverts.”
Tepco is saying that the levels are so high that they can not do any work there now.
“The radiation levels are way too high for workers to get close [to the reactors],” “It’ll certainly take a very long time to inspect the condition of the damaged reactors.”

America will help gain the first good examination of the spent fuel racks in #4 that are listed as possibly damaged on the JAIF status report.http://search.japantimes.co.jp/cgi-bin/nn20110408a5.html
Since workers are unable to approach the spent fuel pool, the U.S. will send a small remote control “micro air vehicle.” to gather images.
This article mentions “U.S. officials especially concerned about the No. 4 reactor, the drone is expected to be first used to examine its radiation levels.”

This was an April 8th article. Any more information on these drone images?

Speaking of the 15 meter tsuanmi that washed over the Fukusima Daichi plant, I have only recent come across this information for the tsuami inundation at the DAINI plant. Tsunami height there seems to be 7m after countermeasures.

“Tokyo Electric Power Company has bugun using unmanned heavy equipment to remove radioactive rubble [from the area around the outside of] the Number One and Number Three reactor buildings. The debris is emitting hundreds of millisieverts of radiation per hour in some places, hindering the restoration work….

Hank, my computer clock tells me that Tokyo time is 1/2 hour ahead of Adelaide time (which is the zone for the times on our comments here). So yes, it’s about 3:30am Tuesday morning in Japan right now.

According to the NSC assessment – already two weeks old – No. 1 to 3 RPV are leaking at least through a pump seal into their primary containment. Notice that despite continues water filling they never manage to rise the water level. No 3 or 4 did likely throw fuel from their SFP into the environment up to a mile away.

The report can be downloaded from a German newspaper that got it hands on it.

Seems Fukushima soon is upgraded to a 7 on the INES-scale.
“The Nuclear Safety Commission of Japan released a preliminary calculation Monday saying that the crippled Fukushima Daiichi nuclear plant had been releasing up to 10,000 terabecquerels of radioactive materials per hour at some point after a massive quake and tsunami hit northeastern Japan on March 11.

The disclosure prompted the government to consider raising the accident’s severity level to 7, the worst on an international scale, from the current 5, government sources said. The level 7 on the International Nuclear Event Scale has only been applied to the 1986 Chernobyl catastrophe.”

> T-hawk drone images (from OregonLive site)
Disappointing blurry distance shots. I hope those are screen-grabs from some low-res television. They’re nothing like the quality the company shows from their hardware. This thing is supposed to be able to hover close up and get imagery down closer than anything else.

I’d expect better closeups from a camera on the end of the concrete pump boom — even using an old mechanical-advance film camera or windup movie camera ‘blind’ with a floodlight attached.

From the document: Fuel particulates may have been ejected from the [Unit 4] pool (based on information of neutron emitters found up to 1 mile from the units, and very high dose rate material that had to be bulldozed over between Units 3 und 4. It is aIso possible the material could have come from Unit 3).

b, “may have” does not mean “did likely” as you say. “Particulates” are not pieces of fuel, as you seem to be implying.

There is an implication that seals on Units 2 and 3 may be leaking. Once again, “may be” is not the same as “is”.

Re the neutron-emitting sources found in the fields around the plant (that they buried with bulldozers) — those should be dug back up eventually to find out what’s emitting and where it came from. We-the-public don’t know if the source was seen and identified, or if the area was identified as hot and quickly buried for short term safety.

Could be particulates, could be chunks — either of those from the fuel pool explosions — or could even be some previously unidentified dump or spill. They’ll want to know, whether we get told or not.

Can someone explain where they’re measuring rates of 20 to 162 Sieverts per hour? Are there working radiation monitors inside the reactor vessels? If so, what is a normal reading for an active reactor?

Kyodo News is reporting that the NSC may increase the INES rating to level 7. Am I right in thinking that this is purely to do with the amount of radiation leaked rather than the potential affect to peoples health? Surely the Japanese have the evacuation situation under control and as such will minimize the dangers to the local population.

“The Nuclear Safety Commission of Japan released a preliminary calculation Monday saying that the crippled Fukushima Daiichi nuclear plant had been releasing up to 10,000 terabecquerels of radioactive materials per hour at some point after a massive quake and tsunami hit northeastern Japan on March 11.

The disclosure prompted the government to consider raising the accident’s severity level to 7. The level 7 on the International Nuclear Event Scale has only been applied to the 1986 Chernobyl catastrophe.”

[Comment deleted. Violation of the citation policy.}MODERATOR
Several commenters are “sailing close to the wind” on the citation policy. This one was the worst with just a “cut and paste” quote plus the link.Borderline overnight violations will not be deleted but further violations today will be.
A reminder to all of the policy:

BARRY BROOK The commenting rules are not meant to be confusing, they’re meant to be logical. This is not a forum for cut-and-pasting slabs of text, with no other comment other than a link. Tell people why you think they should be interesting in reading this, and what it means for this discussion. Otherwise, you’re not thinking and not contributing. Simple as that.
I’ll add a new clause to the commenting rules:
Citing literature and other sources: appropriate and interesting citations and links within comments are welcomed, but please DO NOT cite material that you have not yourself read, digested and understood. As a general rule, please introduce any and every link or reference with a short description of the material, your judgement on its quality, and the specific reason you are including it (i.e. how it is relevant to the discussion).

Please actually read the NHK report linked earlier, which includes: “The agency [NISA] believes the cumulative amount from the Fukushima plant is less than that from Chernobyl.” MODERATOR
The comment you refer to was deleted as a deliberate distortion of the facts – as you picked up on.

[Comment deleted. Wrong thread. Please re-submit to the Fukushima Philosophical Open Thread]MODERATOR
Your personal opinions without supporting scientific references belongs on the Open Thread where commenting rules are more relaxed. We do not have the facility to move comments between threads.

@steve lapp, Not to worry CANDUs can’t fail like the Fukushima Daiichi plant, the design is very different and the areas that nuclear power stations are situated in Ontario are not vulnerable to major earthquakes – and tsunami don’t occur in Lake Ontario.MODERATOR
The comment you refer to was directed to be moved to the Fukushima Philosophical OT.

> between units … in the fields … around
All paraphrases of the original NYT article, I think, which quotes and paraphrases the leaked document it cites as its source:

“The document also suggests that fragments or particles of nuclear fuel from spent fuel pools above the reactors were blown “up to one mile from the units,” and that pieces of highly radioactive material fell between two units and had to be “bulldozed over,” presumably to protect workers at the site.”http://www.nytimes.com/2011/04/06/world/asia/06nuclear.html
—————–
“Suggests” probably means there’s no other credible explanation for finding that material where it was found when it was found, but hey, we don’t know.

Right Hank, we don’t know. The poster known as “b”, however, turned all of the maybes and possibles into definites and probables. (The document itself says “particulates”, never implies “chunks”, and doesn’t say for sure where they came from.)

Regarding the rating: this incident can be classified as a “Major accident” and still not be as bad as Chernobyl. It’s not over yet either; it could get worse.

Reactors at old plants like Fukushima should be replaced with newer designs that aren’t vulnerable to loss of external power events. We’re not just going to stop using nuclear energy– a major source of carbon-free electricity.

Seamus, yes, agreed–it’s very easy to slip from paraphrase into distortion; direct quote with cite is the best we can do, lacking any real information other than what’s made public.

Here are a couple of sites worth looking at, some material I haven’t seen before:http://www.houseoffoust.com/fukushima/R3.html
(and other links there); overlaying the published imagery with graphics and labels from the known layout of the undamaged building, to identify stuff in the mess

(fukushimafaq is a dense site with a lot of material; I’m suggesting it as a place to check out, there’s far more there than I’ve looked at so I’ve only recommended the one link there that I checked into)

Actually ‘BlueRock’ (charmingly polite, as always), it was Joesef Oehman who wrote that, not me, but it was indeed published on this website on 13 March. I agree that the rating should be INES level 7, given the events of the last month (except for the deaths/exposure criteria, see below).

But could you answer me three fairly simple questions:
1. How many people have been killed by radiation as a result of this ‘disaster’? Chernobyl killed 43 workers from severe radiation sickness and another ~15 from cancer that almost certainly resulted from their over-exposure (see this excellent recent piece by Ben Heard: Giving Green the red light). How many in Fukishima?

2. How many members of the public in Japan have been overexposed to radiation as a result of Fukushima? (a bonus sub-question: what is the maximum dose a member of the public is likely to have received?)

3. What is your definition of ‘cognitive dissonance’? (and a bonus sub-question, how does the above fit that definition?)

From TEPCO:
Here are updates on Work Progress at Fukushima Daiichi NPS as of 9:00 pm, April 11.
— There was a aftershock at Hamadori area (close to Fukushima Daiichi and Daini NPS) at 5:16 pm on April 11. Richter scale magnitude was 7.1. All workers in the field evacuated to TSC building in the Fukushima Daiichi site.
Due to the earthquake, off-site power for units 1, 2 and 3 tripped and water injection to the reactor vessel was stopped temporarily. Then the power supply to the pumps resumed at 6:00 pm.
Though no significant damages were made by the earthquake, radioactive water transfer and nitrogen gas injection were suspended.

・ Total amount of injected nitrogen was about 3,000 m3 at 5:00 pm, April 11. Drywell Pressure is 199.0 kPa(abs) at 8:00 pm
・ There was an earthquake at 5:16. Epicenter was Hamadori Region (near Fukushima Daiichi and Daini NPS area) and Richter scale magnitude was 7.1. Due to this earthquake, hydrogen injection pumps stopped. We are checking the status of equipment.
・ When we started nitrogen injection on April 7, we announced that we would continue injection until about 250 kPa (100 kPa above the original pressure), and it would take 6 days. However, drywell pressure has been stable at about 190-195 kPa. We assume there might be some leakage path from the PCV, and because of the leak, drywell pressure does not increase as planned. Considering hydrogen and oxygen generation by water radiolysis, we determined to continue nitrogen gas injection to PCV.

・ Unit 1: Completed transfer from condenser to CST at 9:30 am on April 10.
・ Unit 2: Completed transfer from condenser to CST at 1:30 pm on April 9.
Planning to check for leakage in transfer piping between unit 2 trench to condenser (hotwell).
・ Unit 3: Planning to transfer from condenser to CST.
・ Preparation work to receive radioactive water in the Central Waste Treatment Facility.
> Construction of temporary piping, setting up power supply and installing shields in progress.

・ Completed installment of spillage prevention fences in the south side breakwater. (see picture bellow)
・ On April 12, steal plate is scheduled to be installed in front of the screen room at unit 2, spillage prevention fences (Silt Fence) for units 3 and 4 will be installed.

【Central Waste Treatment Facility 】
– We had discharged approximately 9,070 tons of water (tentative estimation) from the discharge canal of Units 1 to 4 from April 4 to April 10.
– On April 11, we are evaluating the situation after discharge.

【Sub drain of Unit 5 and 6】
– From April 4th, we started the discharge from the water discharge canal of Units 5 & 6 and at 6:52 pm, April 9, we completed it.

・ April 11: About 1,200ｍ２ was sprayed on the mountain side of the common spent fuel pool at 12:00 pm – 1:00 pm.
・ April 12(schedule): About 500ｍ２ will be sprayed on the same location.
> Tentative results of test spraying on April 1 and 5 were as below.
• April 1: Before spray 1 mSv/h –> After 0.8 mSv/h (as of April 3)
• April 5: Before spray 1.6 mSv/h –> After 1.5 mSv/h (as of April 6th)

・ Shooting from the air using the unmanned small chopper: 15:59—16:28, April 10
> Planned flight on April 11 was cancelled due to extra preparation time for setting the devise.
・ Rubble removal using remote control robots: 9:00—16:00, April 11.
> From April 10, two containers (3.2m x 1.6m x 1.1 m) of rubbles were removed.

The Federation of Electric Power Companies of Japan (FEPC) Washington DC Office
As of 11:00AM (EST), April 11, 2011
• Radiation Levels
o The concentration of radioactive nuclides from the seawater sampled at the screen device (installed to remove waste before the intake of seawater) of Unit 2 and sampled near the seawater discharge point (south side) of Fukushima Daiichi Nuclear Station were as follows:
o At 9:00AM (JST) on April 11, radiation level at main gate (approximately 3,281 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 83 micro Sv/hour.
o At 9:00AM on April 11, radiation level at west gate (approximately 3,609 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 45.2 micro Sv/hour.
o Measurement results of environmental radioactivity level around Fukushima Nuclear Power Station announced at 4:00PM on April 11 are shown in the attached PDF file. English version is available at: http://www.mext.go.jp/english/radioactivity_level/detail/1304082.htm
o For comparison, a human receives 2,400 micro Sv per year from natural radiation in the form of sunlight, radon, and other sources. One chest CT scan generates 6,900 micro Sv per scan.

• Fukushima Daiichi Unit 1 reactor
o As of 4:00PM on April 11, injection of nitrogen gas into the primary containment vessel to prevent an explosion by accumulated hydrogen gas continues.
o As of 4:00PM on April 11, the injection of freshwater into the reactor core continues.
• Fukushima Daiichi Unit 2 reactor
o At 10:37AM on April 10, TEPCO began to inject freshwater into the spent fuel pool, until 12:38PM (approximately 60 tons in total).
o As of 4:00PM on April 11, the injection of freshwater into the reactor core continues.
• Fukushima Daiichi Unit 3 reactor
o At 5:15PM on April 10, TEPCO began to shoot freshwater aimed at the spent fuel pool, with a specialized vehicle normally used for pumping concrete, until 7:15PM (approximately 80 tons in total).
o As of 4:00PM on April 11, the injection of freshwater into the reactor core continues.
• Fukushima Daiichi Unit 4 reactor
o At 5:07PM on April 9, TEPCO began to shoot freshwater aimed at the spent fuel pool, with a specialized vehicle normally used for pumping concrete, until 7:24PM (approximately 90 tons in total).
• Fukushima Daiichi Common Spent Fuel Pool
o At 6:30AM on April 11, the temperature of the spent fuel pool: 89.6 degrees Fahrenheit.
• Others
o At 12:14PM on April 8, discharge of approximately 950 tons of low level radioactive water which had accumulated at the sub-drain pits of Unit 5 has completed.
o At 6:52PM on April 9, discharge of approximately 373 tons of low level radioactive water which had accumulated at the sub-drain pits of Unit 6 has completed.
o At 9:00AM on April 10, the removal works of debris at the site began, with a remote controlled excavation machine, until 5:00PM.
o At 8:45AM on April 11, TEPCO began to install a double layered silt fence of approximately 120m (=394 feet) near the south sea wall of Fukushima Daiichi Nuclear Power Station in order to contain the spread of discharged radioactive water, until 10:45AM.

• Fukushima Daiichi Nuclear Power Station
o At 5:40PM on April 11, Unit 1 and 2 lost the external power supply and pumping of freshwater into the reactor core was suspended.
o At 5:56PM on April 11, the external power supply was recovered at Unit 1 and 2.
o At 5:59PM on April 11, pumping of freshwater into the reactor core was suspended for Unit 3.
o At 6:04PM on April 11, pumping of freshwater into the reactor core for Unit 1, 2 and 3 was resumed.
o As of 6:00PM on April 11, no significant changes have been detected at monitoring posts at the site.
o As of 6:05PM on April 11, no abnormality has been reported in the temperature, pressure, or water levels in the reactor cores.
• Fukushima Daini Nuclear Power Station (Unit 1, 2, 3 & 4)
o Plant operation was suspended at all units when the aftershock occurred.
o As of 5:51PM on April 11, no significant changes have been detected at monitoring posts at the site and external power supply was maintained.
• Onagawa Nuclear Power Station (Unit 1,2 & 3)
o Plant operation was suspended at all units when the aftershock occurred.
o As of 5:45PM on April 11, no significant changes have been detected at monitoring posts at the site and external power supply and cooling systems were maintained.
• Higashidori Nuclear Power Station
o Plant was under periodical maintenance when the aftershock occurred.
o As of 6:54PM on April 11, external power supply and cooling systems were maintained.
• Tokai Daini Nuclear Power Station
o Plant operation was suspended when the aftershock occurred.
o As of 5:30PM on April 11, external power supply and cooling systems were maintained.

I really haven’t got a clue why they have raised the INES level to 7 – what exactly does this accomplish, other than to cause more panic and confusion? The authorities must have known there would be an instant media frenzy, and misunderstanding to assume this is now ‘as bad’ or even ‘exactly like Chernobyl’.

I personally do not feel that Fukushima constitutes a INES 7 – ‘Major release of radio­active ­material with widespread health and environmental effects r­equiring implementation of planned and extended ­countermeasures’.

Even level 5 requires ‘Several deaths from ­radiation’ and there have so far been none.

Barry Brook wrote, “How many people have been killed by radiation as a result of this ‘disaster’?”

This question seems rather common around here, but I’m not convinced the answer is that relevant just yet. It’s about the same as asking how many people have been killed by recent climate change so far. Not too many, I guess. Does that mean it isn’t a problem?

It is true that I could be killed quickly by radiation if I stood in front of a hole firing x-rays at my chest or head (like an x-ray tube or synchrotron beam pipe), or from acute exposure to large amounts of radioactive substances. But I was under the impression that the more common health risks from radiation are long-term, cumulative, and insidious.

Unless one is a member of certain populations that may have evolved a resistance to high levels of background radiation (thanks for the Ramsar reference, Cyril R.), one might be wise to pay that some heed.

How many people have been killed by radiation as a result of this disaster so far? Not many. How many will be? I’d imagine it’s harder to say, particularly since we don’t yet know the full nature or scope of releases or contamination. I’m just not sure the question of how many people have died because of a few weeks of possible exposure is that relevant. Isn’t that argument kind of a non-starter?

Huw Jones wrote,
“Even level 5 requires ‘Several deaths from ­radiation’ and there have so far been none.”

It seems it’s an “or”, not an “and” requirement. As in, an incident does not need to fulfill all criteria in order to be considered a certain level. Major release? Check. Extended, planned countermeasures? Check. Level 7.

This question seems rather common around here, but I’m not convinced the answer is that relevant just yet. It’s about the same as asking how many people have been killed by recent climate change so far. Not too many, I guess. Does that mean it isn’t a problem?

This is a fallacious argument. Firstly, I haven’t heard anyone say “this isn’t a problem”. Secondly, comparing it to “how many people have been killed by recent climate change?” is irrelevant, as we only have one global climate, and the problem is cumulative.

This is all about perspective. Nuclear power is one of many energy technologies, and it’s record is sound. Indeed, including Chernobyl, less deaths have been attributed to nuclear energy than any other energy technology*.

So it is completely relevant to ask “How many people have been killed by radiation as a result of this ‘disaster’?” when comparing to other technologies, and it is relevant because of the number of lives it is no doubt saving in places where fossil fuels are not being burned.

The many reasons why the health consequence to the public are still reported as “no measurable effect” need to be emphasized, even while the industry takes the lessons learned seriously and incorporates the nuclear safety improvements that will come from those lessons learned. Reasons like the functioning containment (possible small leak at a torus), the emergency responses to evacuate the 20 Km area, the continued work by site staff with international support to restart fuel cooling and controlled containment venting with winds in the correct direction (when possible) using sea water and accepting the economic consequence for nuclear safety, monitoring personnel dose and ensuring no one suffers life threatening dose, restore power, contain leakage, plans to store highly activated water recovered releasing low active water to the sea the most favorable – least impact dose pathway. The extensive monitoring of dose rates contamination levels vegetation and seafood radiation levels etc to ensure no health impact. Some of these are the results of lessons learned from Chernobyl where lack of evacuations and monitoring would have much reduced the post release consequences to the local public.

The censorship at this site is astounding….It is a fact that many commenters here had said that this will never be a level 7 on the scale of Chernobyl. They are now clearly wrong and I have been censored for pointing this out. [ Comment deleted.Please re-submit with links which show what you claim re TEPCO] These are facts and no amount of censorship on this one-sided website is going to stop them being known.MODERATOR
You were not censored for pointing anything out.If we wished to censor you, your comment would have gone straight to the Trash, as happens all the time on anti-nuclear/green sites. At the time you made your first comment the official line was that a Level 7 was being considered. You commented that it was already so. You were asked not to pre-empt the decision with your own appraisal but to re-post when the determined level was official. The level is a preliminary assessment and still has to be confirmed by the IAEA.Those comments which reported on this, as it had actually occured,were of course let stand.

[Comment deleted. Wrong thread]MODERATOR
This conversation regarding radiation “beliefs” is taking place, and properly belongs, in the Fukushima Philosophical Open Thread. The rules for the OT’s are more relaxed to allow personal opinion not necessarily supported by refs.Please re-post as directed. We do not have the facility to move comments between threads.

I am disappointed by NISA’s summary …Two things jumped out at me: 1) the PCV vents to the refueling floor are not shown. Instead PCV vents to a tall stack are shown (one thru a filter SGTS? and one thru a bursting disc), see slide 21. The PCV vents to the refueling operations floor are shown on the Areva slides and have been thought to be the source of H2 for explosions in R1 and R3 bdlgs. If the PCV vents to the tall stack were used instead of the ones to the refuel floor, then the source of the H2 bdlg explosions could have been instead from the PCV containment cover seals leaking.

There are no pressure release valves or vents from the PCV (or drywell or wetwell) to the refueling floor. This operation cannot be done. The Areva summary is inaccurate on this detail (why they suggested as much is a mystery to me). You would think Areva would know better. But the deliberate venting of gas to the refueling floor never took place, and has never been included in any official accounts: by IAEA, NRC, NEI, NISA, JAIF, TEPCO, and others. I believe the original source for this faulty error are press accounts that simply suggested “there was venting” and “a hydrogen explosion” took place. GE (with the suggestion that “pressure held in primary containment“) and AREVA are two industry sources that have repeated these statements, as well as numerous other enthusiast accounts (such as some included on this site). The implications are as you suggests … a design basis failure of the GE containment Mark I design (likely a release of hydrogen gas to the refueling floor from the flange at the top of the containment vessel), or a failure of venting pathway to the external stack. There are many other penetrations and seals to primary containment, but the flange at the top of the containment vessel (where hydrogen gas is likely to accumulate) is certainly one likely pathway. And pressure tests at the North Carolina Brunswick BWR in the 1970s indicated this is a weak element.

In spite of all the preventive responses to protect the public from radiation so far, level 7 would seem the proper rating of severity considering the reactors are still inaccessible, that no end is yet in sight, and that the wrath of large earthquakes are still occurring, some of which have recently been centered very near the nuclear plant.

Aside from other potentials for an increase in radiation emissions from the reactor core, mentioned in other media, I wonder, is the instability of the region and the threat of something happening that could stop the vital cooling process and elevate emissions of radiation a factor at all in calculating the level to 7?

Some of the strongest quakes of recent have been centered nearly below the Dai-Ichi nuclear plant.http://www.jma.go.jp/en/quake/20110412141747391-121407.html
The tab for ‘Information on seismic intensity at each site’ on that link will show a list of locations, sizes, and a time table of how active it really is.

That article says that the levels of radioactive release could reach that of chernobyl eventually(if not stopped), not admitting that this already happened as your previous comment suggested(you left out the word ‘eventually’).

Question: when does TEPCO run out of qualified workers? I mean workers who have useful remaining radiation allowance.

Hopefully not before all the Daiichi reactors and pools are stable. Nobody knows how many man-hours will prove to be required. But I would like to know at least how fast the existing TEPCO manpower pool is being depleted (I mean their remaining radiological allowances). A week ago WNN reported that 21 out of 370 workers had reached 100 milliseverts [thanks to Hank Roberts 4/11/11 2:01]:

Tom Keen wrote,
“Firstly, I haven’t heard anyone say ‘this isn’t a problem’. Secondly, comparing it to ‘how many people have been killed by recent climate change?’ is irrelevant, as we only have one global climate, and the problem is cumulative.”

Really? I suppose we will just have to disagree then, on both counts. The first is just a matter of personal taste.

But the comparison between the question, “How many people have been killed so far by radiation from the Fukushima Daiichi incident?” and “How many people have been killed so far by recent climate change?” does seem rather relevant to me.

1) The effects are cumulative and long-term.
2) The feedback is not immediate (as it would be if I stood in front of a beam pipe and got irradiated, or ate a gram of neptunium–though I’d likely die from toxicity in that case, not radiation, or perhaps both).
3) The results are not necessarily obvious or easy to deconvolute from other causes (did a person die from radiation exposure or smoking? Did a person die from hunger or climate change?)

These sorts of questions really belong on a more philosophical thread, so I’ll stop here (I only posted here because Prof. Brook raised the question himself).MODERATOR
You are right Mike this does belong on the POT – however I have left it here because of Barry’s comment. Please post any futue comments like this on the POT. Thank you.

John Doe, on 12 April 2011 at 3:40 PM said:
—
That article says that the levels of radioactive release could reach that of chernobyl eventually(if not stopped), not admitting that this already happened as your previous comment suggested(you left out the word ‘eventually’).
—

Nope I used the word “may” in that sentence, and didn’t said that it has occurred. Please read the sentence again before criticising. {On a related matter, Tepco and many other nuclear experts have said that stopping this will take many months and could even be years!} Tell me now how likely will the radioactive release being stopped?MODERATOR
Your comment was deleted as a deliberate distortion of the facts, BECAUSE you misquoted the headline and left out the “may.” You also have failed again to give refs to yourpersonal statements – I have bracketed same.
Your belligerent attitude will not be tolerated on BNC as per the commenting rules. Tone down or you will be banned for violating the rules which aim to keep BNC civil.

A “deterministic health effect” here is something along the lines of acute radiation effects such as sickness. Stochastic health effects are things like cancer. So, I suppose there is still a margin of safety for “deterministic” effects built into the 250 mSv dose limit. For stochastic effects, it’s kind of anybody’s guess–it depends on what model you use to predict risk.MODERATOR
Please move this discussion over to the Fukushima Philosophical OT – see my previous comment. Next comment in the wrong thread will be deleted and you will be asked to re-post. We do not have the facility to move comments between threads.

>>>
Steve Darden, on 12 April 2011 at 3:40 PM said:
Question: when does TEPCO run out of qualified workers? I mean workers who have useful remaining radiation allowance.

I am concerned with that & how even any of the workers can get the plant in control because the workers are not allowed to go inside the reactor buildings. Levels 100mSv are often reached outside the buildings. Radiation up to 500mSv in debris are found outside.

This is a man in the radiation control section of the Dai-Ichi plant in charge of measuring radiation levels and has a vital role in risk measurement.http://www3.nhk.or.jp/nhkworld/english/movie/feature201104052302.html
This is a 1 week old interview with the worker but he said then that radiation levels are so high that restoration work is still only in a preparatory stage and that he felt like a mountain climber looking at a mountain before even beginning to climb it.
Completion of the restoration is nowhere in sight.

[Comment deleted. Violation of the commenting rules]MODERATOR
The rules apply to everyone – you are not special. Personal attacks, tirades, and rudeness will not be tolerated. You are on permanent moderation and will be banned if you persist in this manner.

I don’t think this site is about whether nuclear power is good or evil. Its about educating the public on nuclear energy. For those who post on this site about the virtues on solar power and how horrible nuclear power is, I would suggest reading all the excellent posts on this site and then to go to the Berkeley or MIT site and view their videos on physics and chemistry. After gaining some knowledge about radiation, one can then make an educated judgement on whether nuclear power is beneficial to man kind.

In response to the person who suggested that solar power is the answer if only the government invested in that technology. I posted the math in an earlier blog – the amount of solar panels needed to supply just the US with energy would cover the earth three times. I’m all for solar, wind, wave, ethanol from plants but the numbers show they will never be a major source of energy for the world. Thats reality. We are left with coal, oil, natural gas and nuclear power. Pick your poison.

However, nuclear power technology has made spectacular advances that should alleviate any fears of a nuclear disaster.

@tokyo_reside
———————
“On a related matter, Tepco and many other nuclear experts have said that stopping this will take many months and could even be years! ”
———————

Do they say it will take years to stop the acute radioactive leak, or to clean-up after the disaster? A link to the original statement you are referring to would be welcome, because there’s an important difference between the two(again)

MODERATOR
tokyo_reside has been banned for persistent violations of the commenting rules, including distortions of quotes and therefore facts.
As if to confirm the decision to ban him for violations of the commenting rules, tokyo_reside has re-named himself in various ways and is childishly spamming BNC

[Comment deleted.Wrong thread]MODERATOR
As advised before, this radiation discussion is now taking place in the Fukushima Open Thread, to avoid clogging the current threads with non-relevant information.
Several commenters, including pro-nuclear BNC regulars, have been asked to switch to this thread to continue the arguments.Please re-post your comments there. This version of WordPress does not enable us to move comments between threads.

[[Comment deleted. Wrong thread]MODERATOR
Your previous comments on this topic were in the Fukushima Open Thread. Discussions on alternative power including solar are now on the Fukushima Technical Open Thread. Please post there for these matters. Please do not continue to post on the “Fukushima Daiichi nuclear saga – 2 to 9 April overview” if you wish your comments to avoid deletion.

[Comment deleted. Please re-post on the Fukushima Philosophical Open Thread]MODERATOR
As we have informed you before the “Fukushima Daiichi nuclear saga – 2 to 9 April overview” is not the correct thread to comment on radiation and its effects, death rates etc. You will find this discussion on the above mentioned thread. To avoid deletion of your comments please do not post again on the wrong thread. We would like to simply move the comments between threads but this version of WordPress does not have the facility to do this.

Moderator: I did not introduce these topics (radiation effects et al) you rule as belonging to another thread and that you are dillengently deleting, into this thread, but merely responded to them (other unmoderated commenters introduced these topics). It makes no sense to respond to a comment that in this thread by posting in another thread.MODERATOR
Tom and Mike started this conversation on the wrong thread by mistake and were asked to move over to the Philosophical OT for continuity of discussion – many comments regarding this topic are posted there. Indeed Mike himself, even proposed that he was in the wrong thread and should move. The problem is that when the thread becomes clogged with off-topic remarks, the comments pertinent to the thread drop off as folk get bogged down in non-relevant comments and your position and ideas on the topic are divorced from the main conversation on the OT and will be missed by interested commenters.

Should I move my comment 12 April 2011 at 3:40 PM to Fukushima Technical Open Thread?MODERATOR
I think you would find it a more fruitful area. I must have missed your comment before. Sorry – there has been a lot going on and I have only just got back to the blog to find multitudinous comments have appeared in my absence.

This report from Asahi suggests that some workers did not have dosimeters in the early days of the accident and thus the actual exposure cannot be properly assessed, which could potentially be quite worrisome.This is especially true considering the anisotropy of radiation levels that do not strictly correlate with distance as illustrated by the video posted by Barry from within the exclusion zone. It is reasonable to speculate that within the plant these differences are even larger. Has anyone seen any independent confirmation of this?

dumb question: is the “Central Waste Treatment Facility” for processing of radioactive waste water and if so how effective is this treatment? I query this as I have not seen much uproar about all the contaminated water that must be around the plant. TEPCO did state they dumped low level rad water into the sea so I am guessing that it is not cost efficient to treat it?

also, why not reuse radioactive water into the reactors? no good method to do so?

Solar photovoltaics to produce the present world energy (of all sources) require less than 1% of land area (numerous studies show this). I am not saying that is easily achieved or at present cost effective, but let us not dismiss it outright. We would need in the order of several 100,000 km2 of area, but that is similar to road areas already in place, or to areas of deforestation each year. Big, but not unimaginable.

Where is your source of data for,”However, nuclear power technology has made spectacular advances that should alleviate any fears of a nuclear disaster.”

cheersMODERATOR
You are on the wrong thread.The discussion re solar/alternative energy sources is taking place on the Fukushima Technical and Philosophical Open Threads.

These photos show clearly that the damage pattern in 4 is very different from 1 and 3.

In 1 and 3, all the panels are missing in the top two rows (above the surface of the spent fuel pool), and none are missing “below deck”.

In 4, many panels remain “above deck” and many are missing “below deck.” If hydrogen from the spent fuel pool exploded, how could it have created this pattern of damage? What else could have created it?

If you look at this pic of building 4, you can see what appears to be either an entry or exit hole in the lower right of the building. The rest of this side is in tact. In the lower left foreground you can see some of Unit 3. Perhaps a part of building 3 was blown into the wall of building 4? Or perhaps something was blown out of building 4. Either way, the hole in building 4 is a fascinating clue.

(1) Result of discharge of low level radioactive water to the sea As to the low level radioactive wastewater stored at the Central Radioactive Waste Treatment Facility, we began discharging at 7:03PM, April 4th to the south of the water discharge channel and finished at 5:40PM, April 10th.

At 9:55AM, April 11th, we confirmed that the wastewater in the building had been discharged sufficiently so that the preparation work to accept high level radioactive wastewater in the building could be done.

In relation to the low level radioactive water in sub-drain pits of Units 5 and 6, we began discharging from 9 PM, April 4th via the water discharge channel of Units 5 and 6 and finished by 6:52PM, April 9th.

In terms of the discharge of low level radioactive water to the sea, as instructed by NISA, we have been conducting ocean monitoring in a steadfast manner. We have been increasing the number of monitoring points and the frequency to investigate and confirm the influence of the dispersion of radioactive substances and have been notifying the result.

The radioactive density monitored at the measurement points including near the power station did not indicate significant fluctuation in comparison with the trend one week before the discharge.

We evaluate approximately 0.6 mSv of effective radioactive doses per year for adults as the impact on the discharge of the low radioactive wastewater to the sea if they eat adjacent fish and seaweeds every day. The amount (0.6 mSv of effective radioactive doses per year) is one-forth of annual radioactive dose to which the general public is exposed in nature. The level is similar to the evaluation we made before the discharge to the sea.

With the completion of discharge, as soon as the preparation work completed to accept high level radioactive wastewater at the Central Radioactive Waste Treatment Facility, we will transfer the extremely highly radioactive wastewater in the turbine building of Unit 2 to the Central Radioactive Waste Treatment Facility and store under stable conditions.

Also, from now on, as to the low level radioactive water in sub-drain pits of Units 5 and 6, we will transfer to a temporary outdoor tank and consider an appropriate radiation mitigation plan.

Does anyone have any information on the soil chemistry of the area around Fukushima? most specifically about the mica content in the soil. The reason being is that Cesium behaves like potassium, is fairly easy to take out of water with sunflowers (and a few other plants that also work well) in a rhizofiltration application – thats where there is the best data from the Chernobyl site (Cs contaminated pond water). In soil it can be more difficult depending on the type of clay. Micaceous clays are notorious for fixing K in the clay interlayers – there are small cavities in the clay crystal lattice structure that are a perfect fit for K (and Cs) ions. Once in there, its very difficult if not impossible, to get out without severe treatments to weather the clays. The longer the Cs stays in the soil, the more likely it is to become fixed in the micaceous clays. If you don’t have micas, then the situation is much easier. Thus bioremediation for Cesium removal will be critically dependent on the soil chemistry and early intervention.

Will Davis at Atomic Power Review has two new posts outlining what I speculate will be an important change in TEPCO’s strategy toward reestablishing recirculation cooling of R1, R2, R3. We have been concerned about the complexity and labor-intensity of repairing the original plumbing to support circulatory cooling. Possibly TEPCO has similar concerns, if it is true that their new approach is evidently to construct new primary and secondary cooling, condensing circuits. Here’s Will on 16 April:

(…) The most interesting news of the day is the still developing story that TEPCO has ordered a large number of special heat exchangers, planned for a new external cooling system that it will construct for each reactor plant. This is a novel approach, and probably the best idea TEPCO has had yet. According to the Kyodo story, TEPCO will use several heat exchangers for each plant, and will connect them to the existing external emergency connections that it’s been using prior to this for core injection. Apparently TEPCO will use electric pumps, and two core connections to establish recirculating cooling flow and then use hoses to bring in and return seawater, if we understand the plan correctly. No timeline is given on this plan — but given the mounting complications of the water in the buildings and in the ground, I would have to say that this plan should be given top priority.

I’ve just read the first concrete piece of evidence about how the new systems TEPCO is planning to install will work. Apparently, the idea is to obtain the feed for the pumps from, according to the article, “the reactor containment buildings.” This still isn’t clear, but it does seem to indicate that TEPCO acknowledges the leakage and intends to recycle water in a sort of non-sealed, but closed loop fashion for the primary cooling… the heat from which will be transferred to sea water.

Right now, without any further information, it might be assumed that TEPCO will be taking the water directly from the dry wells or the suppression pools. Important to note is that the primary side of this system will become highly radioactively contaminated, so that the equipment will need to be shielded or else access controlled as the rad level around the equipment will be very high.

My speculation is they will try to flood and circulate the PCV including drywell and wetwell. Any thoughts, comments on this idea?

UPDATE: Kyodo News has a new bulletin that touches on Will’s perspective:

(…) Meanwhile, the utility is considering installing circulating water cooling systems for reactors and spent fuel storage pools outside the reactor buildings at the plant in a bid to bring it under control, sources familiar with the matter said.

The new systems would cool nuclear fuel inside the reactors and spent fuel pools in a stable manner. They would involve heat exchangers and circulation pumps to drain reactor coolant water from the containment buildings, cooling it with seawater and then sending it back to the reactors, the sources said.

The existing circulating water cooling systems at the plant were crippled by the March 11 earthquake and ensuing tsunami.

(…) Radiation levels inside the containment buildings remain high. TEPCO plans to utilize the pipes that it has been using to pump water into the reactors in the new circulating water cooling loops, so it can minimize the need for work inside the dangerous buildings.

Another encouraging tidbit Kyodo News if these unmanned helicopters are more than just Lockheed PR department:

(…) The U.S. government has told Japan that it can use a U.S. unmanned cargo transport helicopter to set up cranes to remove spent fuel rods from storage pools at the crippled Fukushima nuclear power plant, Japanese and U.S. sources close to the matter said Saturday.

The K-MAX helicopter, developed jointly by Lockheed Martin Corp. and KAMAN Aerospace Group of the United States, is being considered to set up the huge cranes.

More TEPCO robot news. It’s much easier to catch these bulletins since I’ve rigged up a full text RSS feed for the Kyodo “nuclear crisis” feed. The full text XML looks like this — another brilliant free service, just insert the ‘fulltextrssfeed.com/’ to any RSS feed that only publishes summaries:

On April 17, TEPCO has announced the Roadmap towards Restoration from the Accident at Fukushima Daiichi Nuclear Power Station.

With regard to the accident at Fukushima Daiichi Nuclear Power Station due to the Tohoku-Chihou-Taiheiyo-Oki Earthquake that occurred on Friday, March 11th, 2011, we are currently making our utmost effort to bring the situation under control. This announcement is to notify the roadmap that we have put together towards restoration from the accident.

1. Basic Policy
By bringing the reactors and spent fuel pools to a stable cooling condition and mitigating the release of radioactive materials, we will make every effort to enable evacuees to return to their homes and for all citizens to be able to secure a sound life.

2. Targets
Based on the basic policy, the following two steps are set as targets:

Step1. “Radiation dose is in steady decline” (our target is in about 3 months) Step2. “Release of radioactive materials is under control and radiation dose is being significantly held down” (3 to 6 months after achieving Step1) Step3. ” Target achievement dates are tentatively set as follows

TEPCO’s briefing slides (4) are available here. My speculation that they would flood the PCV appears to be correct:

Countermeasure [9]: Flood the PCV up to the top of active fuel.

I agree with David – if they achieve their objectives in 9 months I will be impressed and relieved. My understanding is that TEPCO knows little about the actual state of the machinery inside the buildings. And they have no experience of doing such construction in a hot environment – with or without robots.

Update to Information Sheet Regarding the Tohoku EarthquakeThe Federation of Electric Power Companies of Japan (FEPC) Washington DC Office
As of 11:30AM (EST), April 18, 2011
• Roadmap
o On April 17, TEPCO announced “the Roadmap towards Restoration from the Accident at Fukushima Daiichi Nuclear Power Station.” This will be sent by another email and is also available at:http://www.tepco.co.jp/en/press/corp-com/release/11041707-e.html
• Radiation Levels
o On April 17, TEPCO announced the result of the analysis of water samples from the skimmer surge tank (installed to receive the overflowed water and floating wastes) of the spent fuel pool at Unit 2 of Fukushima Daiichi Nuclear Power Plant taken on April 16.
o At 4:00PM (JST) on April 18, radiation level at main gate (approximately 3,281 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 61 micro Sv/hour.
o At 4:00PM on April 18, radiation level at west gate (approximately 3,609 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 31.4 micro Sv/hour.
o Measurement results of environmental radioactivity level around Fukushima Nuclear Power Station announced at 4:00PM on April 18 are shown in the attached PDF file. English version is available at: http://www.mext.go.jp/english/radioactivity_level/detail/1304082.htm
o For comparison, a human receives 2,400 micro Sv per year from natural radiation in the form of sunlight, radon, and other sources. One chest CT scan generates 6,900 micro Sv per scan.
• Fukushima Daiichi Unit 1 reactor
o At 4:00PM on April 17, the surveillance of the reactor building began, with a remote controlled robot, until 5:30PM.
o As of 5:00PM on April 18, injection of nitrogen gas into the primary containment vessel to prevent an explosion by accumulated hydrogen gas continues.
o As of 5:00PM on April 18, the injection of freshwater into the reactor core continues.
• Fukushima Daiichi Unit 2 reactor
o At 10:13AM on April 16, TEPCO began to inject freshwater into the spent fuel pool, until 11:54AM (approximately 45 tons in total).
o At 1:42PM on April 18, the surveillance of the reactor building began, with a remote controlled robot, until 2:33PM.
o As of 5:00PM on April 18, the injection of freshwater into the reactor core continues.
• Fukushima Daiichi Unit 3 reactor
o At 11:30AM on April 17, the surveillance of the reactor building began, with a remote controlled robot, until 2:00PM.
o At 2:17PM on April 18, TEPCO began to shoot freshwater aimed at the spent fuel pool, with a specialized vehicle normally used for pumping concrete, until 3:02PM (approximately 30 tons in total).
o As of 5:00PM on April 18, the injection of freshwater into the reactor core continues.
• Fukushima Daiichi Unit 4 reactor
o At 5:39PM on April 17, TEPCO began to shoot freshwater aimed at the spent fuel pool, with a specialized vehicle normally used for pumping concrete, until 9:22PM (approximately 140 tons in total).
• Fukushima Daiichi Common Spent Fuel Pool
o At 2:34PM on April 17, the power supply to the spent fuel pool was temporarily interrupted due to an electrical short circuit.
o At 5:30PM on April 17, the power supply to the spent fuel pool was restored after the removal of the cable and checkups.
o As of 4:30AM on April 18, the temperature of the spent fuel pool: 91.4 degrees Fahrenheit.
• Others
o At 9:00AM on April 15, TEPCO began to install silt barrier containing zeolite (an absorbent of radioactive nuclides) between the screen pump rooms of Unit 1 and 2 and between the screen pump rooms of Unit 2 and 3, until 11:15AM.
o At 10:19AM on April 15, TEPCO began to transfer distribution panels of the pumps to inject water to the reactors of Units 1 to 3 to higher ground as a countermeasure against tsunami, until 5:00PM.
o At 2:30PM on April 15, TEPCO began to install silt barrier containing zeolite between the screen pump rooms of the Unit 3 and Unit 4.
o At 9:00AM on April 16, the removal works of debris at the site began, with a remote controlled excavation machine, until 4:00PM.
o At 9:00AM on April 17, the removal works of debris at the site began, with a remote controlled excavation machine, until 4:00PM.

You’ve also read likely it elsewhere, but I continue to find WNN much clearer than the various MSM articles, those by non-experts at matters nuclear. Alos, a few minor points not covered in some other articles.

KBMAN has just posted a new commentary, which includes a thumbnail of the analysis by the Atomic Energy Society of Japan:

Nuclear fuel inside the crippled reactors at the Fukushima Daiichi power plant has partially melted and settled in granular form at the bottom of pressure vessels, according to an analysis by the Atomic Energy Society of Japan made public by Friday.

…

The academic body’s panel on nuclear energy safety has said the melted fuel at the Nos. 1 to 3 reactors has been kept at a relatively low temperature, discounting the possibility that a large amount of melted fuel has already built up at the bottom of the reactor vessels given the temperature readings there.

A large buildup of melted nuclear fuel could transform into a molten mass so hot that it could damage the critical containers and eventually leak huge amounts of radioactive materials.

The panel has also said that the fuel grains with a diameter of between several millimeters and 1 centimeter are believed to have settled evenly at the bottom of the vessels, leaving almost no possibility of a nuclear chain reaction called ”recriticality.”

I am putting this post in this thread in additional to the technical thread. It seems more action is here.

The following is a quote from a WSJ article in this mornings WSJ

“Under its strategic plan unveiled Sunday, Tepco is planning to fill the containment vessels of the plant’s No. 1 and No. 3 reactor units with water and employ heat-exchanging systems that could include an air-cooling solution. Similar plans are in place for the heavily damaged No. 2 reactor unit but must await the repair of leaks that are allowing the escape of highly radioactive water contaminated by the damaged fuel rods.”

As read from the quote above, Tepco is planning to fill the “containment” vessels.

This must be an error. I think they are just going to cool the water in the PRV by creating a new closed loop cooling system for the RPV and cooling this loop via an air cooled heat exchanger similer to french design. I would assume also that the air cooling would consist of an evap cooling tower.

Thx for the response.
I put my original post today about CV flooding in the technical blog also and have gotten more responses so let’s move the CV flooding discussion over there.

OK ??

PS The JAIF update has said the same for some time now yes?? (I could be wrong).
Do you have a link for the AREVA presentation that says they flooded R1?? How could they send a robot into that CV if it is flooded??